1. Technical Field
This invention relates generally to dynamic oil seals, and more particularly to radial shaft seals.
2. Related Art
Dynamic radial shaft oil seals are designed to have a so-called “oil-side” of the seal and an “air-side.” These designations pertain to the orientation of the seal when installed, with the oil-side facing the interior of the housing and being in communication with the oil, whereas the air-side faces outwardly and is exposed to the air.
During use, it is desirable to keep dust and other contaminants on the air-side of the seal while maintaining lubrication on the oil-side of the seal. It is known to incorporate spiral grooves in a seal lip to pump lubrication back to the oil-side of the seal, however, these grooves are not infallible. When oil flows past the grooves, it is generally free to reach the air-side of the seal, which not only depletes the oil supply, but, in addition to making an unsightly mess and further causing the build-up of dust and debris within the oil accumulated on the air-side of the seal, requires servicing and replacement of the seal, which can be costly. Accordingly, what is needed is a seal that both reliable keeps contaminants on an air-side of the seal from reaching an oil-side of the seal, while at the same time, preventing the egress of lubrication on the oil-side of the seal from reaching the air-side of the seal.